Nowadays flat display technology has been widely applied to various types of display panels and products, such as liquid crystal display devices, mobile phones, and media players. As manufacturing processes are improved, gate driving circuits can be manufactured on an array substrate of the display panel for now. This is called a “gate on array” (GOA) technology and is supplanting the traditional manufacturing and packaging process of gate driving ICs; also it is capable of reducing the manufacturing cost and additional costs of materials and/or components.
FIG. 1 is a schematic diagram showing a conventional display panel driving voltage supply apparatus 10 for providing a display panel 1 with a driving voltage. The display panel 1 has a plurality of gate driving circuits, such as 151, 152, which are disposed thereon. The conventional display panel driving voltage supply apparatus 10 comprises a timing controller (T-CON) 12, a level shifter 14, and a first driving voltage supply line 101 and a second driving voltage supply line 102 coupled to the level shifter 14. The timing controller 12 outputs voltage control signals (e.g. CKV, CKVB) to the level shifter 14. The level shifter 14 has two terminals being inputted respectively with a first specified voltage and a second specified voltage such as 27V and −13V.
In the conventional display panel driving voltage supply apparatus 10, the level shifter 14 selects the first specified voltage to be transmitted on the first driving voltage supply line 101 and selects the second specified voltage to be transmitted on the second driving voltage supply line 102 according to the voltage control signals. For example, the level shifter 14 selects to output the first specified voltage 27V when the voltage control signal is at a high voltage level, and the level shifter 14 selects to output the second specified voltage −13V when the voltage control signals is at a low voltage level. Moreover, when the voltage control signal CKV is at the high voltage level, the voltage control signal CKVB will be at the low voltage level. Conversely, when the voltage control signal CKV is at the low voltage level, the voltage control signal CKVB will be at the high voltage level. Therefore, a first voltage supply signal CKV1 on the first driving voltage supply line 101 has a voltage variation of 40V. A second voltage supply signal CKVB1 on the second driving voltage supply line 102 also has a voltage variation of 40V.
As shown in FIG. 1, the first voltage supply signal CKV1 and the second voltage supply signal CKVB1 on the two driving voltage supply lines 201, 202, provide voltages to the respective gate driving circuits, e.g. 151, 152, so that the gate driving circuits output scan signals Gout1, Gout2, to the scan lines or gate lines on the display panel 1.
Since the voltage of the first voltage supply signal CKV1 on the first driving voltage supply line 101 is varied from −13V to 27V, and the voltage of the second voltage supply signal CKVB1 on the second driving voltage supply line 102 is varied from 27V to −13V for the same period of time, the operational voltage difference is spanned about 40V. In the conventional display panel driving voltage supply apparatus 10, the power consumption is too high and electricity is heavily consumed. This does not meet the requirements of designing environmental green products.
Therefore, how to solve the problem of high power consumption of the conventional display panel driving voltage supply apparatus and reduce the electricity consumption are important issues in this technical field.